Triacanthine enhances the sensitivity of colorectal cancer cells to 5-fluorouracil by regulating RRM2.

BACKGROUND: According to the literatures, triacanthine is isolated from the leaves of Gleditsia triacanthos L. and acts as an anti-hypertensive agent, also cardiotonic, antispasmodic and a respiratory analeptic. The 5-fluorouracil (5-FU) is widely used to treat the patients of colorectal cancer (CRC), but the resistance to 5-FU treatment restricts the therapeutic efficacy of CRC patients. PURPOSE: This study aims to explore a novel therapeutics regimen overcoming CRC resistance to 5-FU. METHODS: The cell proliferation of CRC cells was determined by SRB and colony formation assay. Transwell and wound-healing assay were applied to explore the potential metastatic abilities of CRC cells. qRT-PCR and Western blot were performed to evaluate the level of indicated mRNAs and proteins respectively. Xenograft assay was used to explore the anti-CRC effect of triacanthine. RESULTS: Triacanthine statistically restrained CRC proliferation both in vitro and in vivo. Triacanthine induced cell cycle G1/G0 phase arrest in CRC cells. Meanwhile, triacanthine also inhibited the migrative and invasive abilities of CRC cells. A Venn diagram was generated showing that O-6-Methylguanine-DNA Methyltransferase (MGMT) might be a molecular target of triacanthine in treating CRC. Furthermore, triacanthine plus 5-FU significantly suppressed the cell proliferation of CRC cells compared with single agent treatment alone, and highly synergistic anti-cancer effects were scored when 5-FU was combined with triacanthine in CRC cells. In addition, triacanthine sensitized the anti-cancer activity of 5-FU via regulating Ribonucleotide Reductase Regulatory Subunit M2 (RRM2). MGMT or RRM2 might be novel biomarkers for evaluating the therapeutical efficiency of 5-FU in CRC patients. CONCLUSION: We firstly demonstrated triacanthine suppressed cell proliferation and metastasis abilities and found the novel molecular targets of triacanthine in CRC cells. This is the first study to evaluate the anti-cancer efficiency of triacanthine plus 5-FU. Our study has revealed triacanthine as a pertinent sensitizer to 5-FU, and provided novel strategies for predicting outcomes and reversing resistance of 5-FU therapy.

DSCC1 interacts with HSP90AB1 and promotes the progression of lung adenocarcinoma via regulating ER stress.

Lung cancer is a leading cause of cancer-related deaths, and the most common type is lung adenocarcinoma (LUAD). LUAD is frequently diagnosed in people who never smoked, patients are always diagnosed at advanced inoperable stages, and the prognosis is ultimately poor. Thus, there is an urgent need for the development of novel targeted therapeutics to suppress LUAD progression. In this study, we demonstrated that the expression of DNA replication and sister chromatid cohesion 1 (DSCC1) was higher in LUAD samples than normal tissues, and the overexpression of DSCC1 or its coexpressed genes were highly correlated with poor outcomes of LUAD patients, highlighting DSCC1 might be involved in LUAD progression. Furthermore, the expression of DSCC1 was positively correlated with multiple genetic mutations which drive cancer development, including TP53, TTN, CSMD, and etc. More importantly, DSCC1 could promote the cell proliferation, stemness, EMT, and metastatic potential of LUAD cells. In addition, DSCC1 interacted with HSP90AB1 and promoted the progression of LUAD via regulating ER stress. Meanwhile, DSCC1 expression negatively correlated with immune cell infiltration in lung cancer, and DSCC1 positively regulated the expression of PD-L1 in LUAD cells. Collectively, this study revealed that DSCC1 is a novel therapeutic target to treat LUAD and a biomarker for predicting the efficiency of PD-1/PD-L1 blockade treatment.

Recent research progress of circular RNAs in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is an extremely heterogeneous malignant tumor with a high morbidity and mortality. Circular RNAs (circRNAs) are noncoding RNAs with high stability, organ/tissue/cell-specific expression and are conserved across species. Accumulating evidence suggested that circRNAs play crucial roles as microRNA sponges, protein sponges, scaffolds, recruiters and could even polypeptide encoders. Many studies have since revealed that circRNAs were aberrantly expressed in HCC and acted as crucial modulators of HCC carcinogenesis and progression. Furthermore, circRNAs have also been identified as potential diagnostic and prognostic biomarkers for HCC. In this review, we thoroughly outline and evaluate the function of circRNAs in HCC development, with an emphasis on the specific molecular pathways by which they participated in the formation and progression of HCC, and we address their potential for serving as clinical biomarkers in HCC.

DYRK1A reinforces epithelial-mesenchymal transition and metastasis of hepatocellular carcinoma via cooperatively activating STAT3 and SMAD.

BACKGROUND: Hepatocellular carcinoma (HCC) accounts for the majority of liver cancer cases, while metastasis is considered the leading cause of HCC-related death. However, the currently available treatment strategies for efficient suppression of metastasis are limited. Therefore, novel therapeutic targets to inhibit metastasis and effectively treat HCC are urgently required. METHODS: Wound healing and Transwell assays were used to determine the migration and invasion abilities of HCC cells in vitro. Quantitative real-time PCR (qRT-PCR), protein array, immunofluorescence, and immunoprecipitation experiments were used to study the mechanism of DYRK1A-mediated metastasis. A tail vein metastasis model and H&E staining were utilized to assess metastatic potential in vivo. RESULTS: The results of the current study demonstrated that dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) was upregulated in HCC tissues compared with normal liver tissues. Additionally, the level of DYRK1A was increased in primary HCC tissues of patients with metastasis compared with those of patients without metastasis, and DYRK1A overexpression correlated with worse outcomes in liver cancer patients. Gain- and loss-of-function studies suggested that DYRK1A enhanced the invasion and migration abilities of HCC cells by promoting epithelial-mesenchymal transition (EMT). Regarding the promoting effect of DYRK1A on cell invasion, the results showed that DYRK1A was coexpressed with TGF-ß/SMAD and STAT3 signalling components in clinical tumour samples obtained from patients with HCC. DYRK1A also activated TGF-ß/SMAD signalling by interacting with tuberous sclerosis 1 (TSC1) and enhanced metastasis of HCC cells by activating STAT3. Furthermore, DYRK1A promoted EMT by cooperatively activating STAT3/SMAD signalling. CONCLUSION: Overall, the present study not only uncovered the promoting effect of DYRK1A on HCC metastasis and revealed the mechanism but also provided a new approach to predict and treat metastatic HCC.

Decreased INPP5B expression predicts poor prognosis in lung adenocarcinoma.

BACKGROUND: Inositol Polyphosphate-5-Phosphatase B (INPP5B), a inositol 5-phosphatase, plays an important role in many biological processes through phosphorylating PI(4,5)P2 and/or PI(3,4,5)P3 at the 5-position. Nevertheless, little is known about its function and cellular pathways in tumors. This study aims to investigate the potential role of INPP5B as a diagnostic and prognostic biomarker for lung adenocarcinoma (LUAD), as well as its biological functions and molecular mechanisms in LUAD. METHODS: TCGA, GEO, CTPAC, and HPA datasets were used for differential expression analysis and pathological stratification comparison. The prognostic and diagnostic role of INPP5B was determined by Kaplan-Meier curves, univariate and multivariate Cox regression analysis, and receiver operating characteristics (ROC) curve analyses. The potential mechanism of INPP5B was explored through GO, KEGG, and GSEA enrichment analysis, as well as GeneMANIA and STRING protein-protein interaction (PPI) network. PicTar, PITA, and miRmap databases were used for exploring miRNA targeting INPP5B. In molecular biology experiments, immunohistochemical analyses and Western blot analyses were used to determine protein expression. Co-immunoprecipitation assay was used to detect protein-protein interactions. CCK8 assays and colony formation assays were used for the measurement of cell proliferation. Cell cycle was assessed by PI staining with flow cytometry. Cell migration was performed by Transwell assays and wound healing assays. RESULT: INPP5B was decreased in LUAD tissues compared with normal adjacent tissues. And the low expression of INPP5B was associated with late-stage pathological features. In addition, INPP5B was found to be a significant independent prognostic and diagnostic factor for LUAD patients. Hsa-miR-582-5p was predicted as a negative regulator of INPP5B mRNA expression. INPP5B was significantly correlated with the expression of PTEN and the activity of PI3K/AKT signaling pathways, as determined by enrichment analysis and PPI network. In vitro experiments partially confirmed the aforementioned findings. INPP5B could interact directly with PTEN. INPP5B overexpression inhibited LUAD cell proliferation and migration while downregulating the AKT pathway. CONCLUSION: Our results demonstrated that INPP5B could inhibit the proliferation and metastasis of LUAD cells. It could serve as a novel diagnostic and prognostic biomarker for LUAD patients. Trial registration LUAD tissues and corresponding para-cancerous tissues were collected from 10 different LUAD patients at Hangzhou First People's Hospital. The Ethics Committee of Hangzhou First People's Hospital has approved this study. (registration number: IIT-20210907-0031-01; registration date: 2021.09.13).

DYRK1A suppression attenuates HIF­1α accumulation and enhances the anti­liver cancer effects of regorafenib and sorafenib under hypoxic conditions.

Hypoxia promotes drug resistance and induces the expression of hypoxia inducible factor (HIF)­1α in liver cancer cells. However, to date, no selective HIF­1α inhibitor has been clinically approved. The aim of this study is to investigate a drug­targetable molecule that can regulate HIF­1α under hypoxia. The present study demonstrated that hyperactivation of dual­specificity tyrosine­phosphorylation­regulated kinase 1A (DYRK1A)/HIF­1α signaling was associated with an increased risk of liver cancer. In addition, DYRK1A knockdown using small interfering RNA transfection or treatment with harmine, a natural alkaloid, significantly reduced the protein expression levels of HIF­1α in liver cancer cells under hypoxic conditions in vitro. Conversely, DYRK1A overexpression­vector transfection in liver cancer cell lines notably induced HIF­1α expression under the same conditions. Furthermore, DYRK1A was shown to interact and activate STAT3 under hypoxia to regulate HIF­1α expression. These findings indicated that DYRK1A may be a potential upstream activator of HIF­1α and positively regulate HIF­1α via the STAT3 signaling pathway in liver cancer cells. Additionally, treatment with harmine attenuated the proliferative ability of liver cancer cells under hypoxic conditions using sulforhodamine B and colony formation assay. Furthermore, DYRK1A knockdown could significantly enhance the anti­liver cancer effects of regorafenib and sorafenib under hypoxia. Co­treatment with harmine and either regorafenib or sorafenib also promoted cell death via the STAT3/HIF­1α/AKT signaling pathway under hypoxia using PI staining and western blotting. Overall, the results from the present study suggested that DYRK1A/HIF­1α signaling may be considered a novel pathway involved in chemoresistance, thus providing a potentially effective therapeutic regimen for treating liver cancer.

Enhanced anticancer activity by the combination of vinpocetine and sorafenib via PI3K/AKT/GSK-3ß signaling axis in hepatocellular carcinoma cells.

Vinpocetine is widely used to treat cerebrovascular diseases. However, the effect of vinpocetine to treat hepatocellular carcinoma (HCC) has not been investigated. In this study, we revealed that vinpocetine was associated with antiproliferative activity in HCC cells, but induced cytoprotective autophagy, which restricted its antitumor activity. Autophagy inhibitors improved the antiproliferative activity of vinpocetine in HCC cells. Sorafenib is effective to treat advanced HCC, but the effect of autophagy induced by sorafenib is indistinct. We demonstrated vinpocetine plus sorafenib suppressed the cytoprotective autophagy activated by vinpocetine in HCC cells and significantly induced apoptosis and suppressed cell proliferation in HCC cells. In addition, vinpocetine plus sorafenib activates glycogen synthase kinase 3ß (GSK-3ß) and subsequently inhibits cytoprotective autophagy induced by vinpocetine in HCC cells. Meanwhile, overexpression of GSK-3ß was efficient to increase the apoptosis induced by vinpocetine plus sorafenib in HCC cells. Our study revealed that vinpocetine plus sorafenib could suppress the cytoprotective autophagy induced by vinpocetine and subsequently show synergistically anti-HCC activity via activating GSK-3ß and the combination of vinpocetine and sorafenib might reverse sorafenib resistance via the PI3K/protein kinase B/GSK-3ß signaling axis. Thus, vinpocetine may be a potential candidate for sorafenib sensitization and HCC treatment, and our results may help to elucidate more effective therapeutic options for HCC patients with sorafenib resistance.

ApoC1 promotes the metastasis of clear cell renal cell carcinoma via activation of STAT3.

Clear cell renal cell carcinoma (ccRCC) is the most common renal cancer and frequently diagnosed at an advanced stage. It is prone to develop unpredictable metastases even with proper treatment. Antiangiogenic therapy is the most effective medical treatment for metastatic ccRCC. Thus, exploration of novel approaches to inhibit angiogenesis and metastasis may potentially lead to a better therapeutic option for ccRCC. Among all the types of cancer, renal cancer samples exhibited the maximum upregulation of ApoC1 as referred to in the Oncomine database. The expression of ApoC1 was increased accompanied by ccRCC progression. A high level of ApoC1 was closely related to poor survival time in ccRCC patients. Furthermore, ApoC1 was over-expressed in the highly invasive ccRCC cells as compared to that in the low-invasive ccRCC cells. Besides, ApoC1 promoted metastasis of ccRCC cells via EMT pathway, whereas depletion of ApoC1 alleviated these effects. ApoC1 as a novel pro-metastatic factor facilitates the activation of STAT3 and enhances the metastasis of ccRCC cells. Meanwhile, ApoC1 in the exosomes were transferred from the ccRCC cells to the vascular endothelial cells and promoted metastasis of the ccRCC cells via activating STAT3. Finally, the metastatic potential of the ccRCC cells driven by ApoC1 was suppressed by DPP-4 inhibition. Our study not only identifies a novel ApoC1-STAT3 pathway in ccRCC metastasis but also provides direction for the exploration of novel strategies to predict and treat metastatic ccRCC in the future.

A natural anthraquinone derivative shikonin synergizes with AZD9291 against wtEGFR NSCLC cells through reactive oxygen species-mediated endoplasmic reticulum stress.

BACKGROUND: NSCLC is the major type of lung cancer and the survival rates of NSCLC patients remain low. AZD9291 is a third-generation EGFR-TKI and approved to treat NSCLC patients harboring EGFR T790M mutation and common targetable activating EGFR mutations, but it has a limited effect for wtEGFR NSCLC. PURPOSE: The current study investigated whether shikonin could enhance the antitumor effect of AZD9291 in wtEGFR NSCLC cells. METHODS: SRB and colony formation assay were used to detect the proliferation of NSCLC cells, propidium iodide staining was performed to detect the apoptosis, ROS was analyzed using DCFH-DA staining, and western blot was used to detect the expression of indicated proteins. RESULTS: We demonstrated that shikonin, a natural ROS inducer, could enhance the antitumor effect of AZD9291 in wtEGFR NSCLC cells. In addition, shikonin increased AZD9291-induced apoptosis accompanying with the generation of ROS and activation of ER stress. Furthermore, ROS inhibition by NAC or GSH reversed the apoptosis induced by shikonin plus AZD9291, and recovered the ER stress activated by combination treatment, indicating that ROS mediated ER stress played a vital role in this combination therapy. Moreover, shikonin increased the anticancer activity of AZD9291 in primary wtEGFR NSCLC cells through ROS-mediated ER stress. CONCLUSION: Our study suggests that combining shikonin with AZD9291 is a promising therapeutic strategy for treating wtEGFR NSCLC patients.

DYRK1A inhibition suppresses STAT3/EGFR/Met signalling and sensitizes EGFR wild-type NSCLC cells to AZD9291.

DYRK1A is considered a potential cancer therapeutic target, but the role of DYRK1A in NSCLC oncogenesis and treatment requires further investigation. In our study, high DYRK1A expression was observed in tumour samples from patients with lung cancer compared with normal lung tissues, and the high levels of DYRK1A were related to a reduced survival time in patients with lung cancer. Meanwhile, the DYRK1A inhibitor harmine could suppress the proliferation of NSCLC cells compared to that of the control. As DYRK1A suppression might be effective in treating NSCLC, we next explored the possible specific molecular mechanisms that were involved. We showed that DYRK1A suppression by siRNA could suppress the levels of EGFR and Met in NSCLC cells. Furthermore, DYRK1A siRNA could inhibit the expression and nuclear translocation of STAT3. Meanwhile, harmine could also regulate the STAT3/EGFR/Met signalling pathway in human NSCLC cells. AZD9291 is effective to treat NSCLC patients with EGFR-sensitivity mutation and T790 M resistance mutation, but the clinical efficacy in patients with wild-type EGFR remains modest. We showed that DYRK1A repression could enhance the anti-cancer effect of AZD9291 by inducing apoptosis and suppressing cell proliferation in EGFR wild-type NSCLC cells. In addition, harmine could enhance the anti-NSCLC activity of AZD9291 by modulating STAT3 pathway. Finally, harmine could enhance the anti-cancer activity of AZD9291 in primary NSCLC cells. Collectively, targeting DYRK1A might be an attractive target for AZD9291 sensitization in EGFR wild-type NSCLC patients.

BAY 87-2243 sensitizes hepatocellular carcinoma Hep3B cells to histone deacetylase inhibitors treatment via GSK-3ß activation.

Hepatocellular carcinoma (HCC) is associated with some of the highest cancer-associated mortality rates. Histone deacetylase (HDAC) inhibitors anti-HCC activities have been shown to promote Snail-induced metastasis. In the present study, it was shown that BAY 87-2243, a hypoxia-inducible transcription factor-1α inhibitor, could enhance the anti-HCC effects of HDAC inhibitors, including trichostatin A and vorinostat. In addition, BAY 87-2243 plus HDAC inhibitors exhibited synergistic cytotoxicity and induced significant cell death in Hep3B cells. Additionally, BAY 87-2243 combined with HDAC inhibitors-treated Hep3B cells formed fewer and smaller colonies as compared with either the control or single agent-treated cells. Furthermore, glycogen synthase kinase-3ß might be involved in the enhanced cell death induced by BAY 87-2243 plus HDAC inhibitors. The present data also indicated that BAY 87-2243 combined with HDAC inhibitors could suppress the migration of Hep3B cells, and BAY 87-2243 could reverse the HDAC inhibitor-induced Snail activation in Hep3B cells. In conclusion, BAY 87-2243 combined with HDAC inhibitors might be an attractive chemotherapy strategy for HCC therapy.

KLF4 functions as an oncogene in promoting cancer stem cell-like characteristics in osteosarcoma cells.

Despite more effective chemotherapy combined with limb-salvage surgery for the osteosarcoma treatment, survival rates for osteosarcoma patients have stagnated over the past three decades due to the poor prognosis. Osteosarcoma cancer stem cells (OSCs) are responsible for the growth and metastasis of osteosarcoma. The existence of OSCs offers a theoretical explanation for therapeutic failures including tumor recurrence, metastasis, and drug resistance. Understanding the pathways that regulate properties of OSCs may shed light on mechanisms that lead to osteosarcoma and suggest better modes of treatment. In this study, we showed that the expression level of Kruppel-like factor 4 (KLF4) is highly associated with human osteosarcoma cancer stemness. KLF4-overexpressed osteosarcoma cells displayed characteristics of OSCs: increased sphere-forming potential, enhanced levels of stemness-associated genes, great chemoresistance to adriamycin and CDDP, as well as more metastasis potential. Inversely, KLF4 knockdown could reduce colony formation in vitro and inhibit tumorigenesis in vivo, supporting an oncogenic role for KLF4 in osteosarcoma pathogenesis. Furthermore, KLF4 was shown to activate the p38 MAPK signaling pathway to promote cancer stemness. Altogether, our studies uncover an essential role for KLF4 in regulation of OSCs and identify KLF4-p38 MAPK axis as a potential therapeutic target for osteosarcoma treatment.

Shikonin sensitizes wild­type EGFR NSCLC cells to erlotinib and gefitinib therapy.

As patients with non­small cell lung cancer (NSCLC) and wild­type epidermal growth factor receptor (EGFR) are resistant to treatment with erlotinib or gefitinib, potential chemosensitizers are required to potentiate wild­type EGFR NSCLC cells to erlotinib/gefitinib treatment. The present study reported that shikonin could sensitize the anticancer activity of erlotinib/gefitinib in wild­type EGFR NSCLC cells. Furthermore, shikonin could potentiate mitochondrial­mediated apoptosis induced by erlotinib/gefitinib in wild­type EGFR NSCLC cells. In addition, the present study demonstrated that shikonin could induce apoptosis by activating reactive oxygen species (ROS)­mediated endoplasmic reticulum (ER) stress, and that erlotinib/gefitinib may also induce ER stress in wild­type EGFR NSCLC cells; however, shikonin plus erlotinib/gefitinib was more effective in activating ER stress than either agent alone. This indicated that ROS­mediated ER stress may be associated with enhanced mitochondrial apoptosis induced by shikonin plus erlotinib/gefitinib. In addition, shikonin may promote the transition of cytoprotective ER stress­inducing EGFR­tyrosine kinase inhibitor tolerance to apoptosis­promoting ER stress. Furthermore, shikonin may enhance the anti­NSCLC activity of erlotinib/gefitinib in vivo. The data of the present study indicated that shikonin may be a potential sensitizer to enhance the anti­cancer efficacy of erlotinib/gefitinib in wild­type EGFR NSCLC cells resistant to erlotinib/gefitinib treatment.

The anti-tumor effect of regorafenib in lung squamous cell carcinoma in vitro.

Lung squamous cell carcinoma (LSCC) is a common type of non-small-cell lung cancer (NSCLC) and lacks effective treatment. Regorafenib, an oral multikinase inhibitor, has demonstrated promising anti-tumor activity in various solid tumors. To study whether regorafenib inhibits LSCC cells, we investigate the compound in several LSCC cell lines and explore the possible mechanism. In this study, we confirmed that regorafenib had anti-proliferation effect on LSCC cell lines by inducing G0/G1 arrest. In addition, glycogen synthase kinase 3ß (GSK3ß) remained at the same level and Ser9 phosphorylation of GSK3ß decreased with increasing incubation time and increasing regorafenib concentration in LSCC cells. GSK3ß inhibition enhanced the anti-tumor activity of regorafenib. Thus, GSK3ß activation restricted the anti-cancer effect of regorafenib on LSCC. In conclusion, regorafenib might be a promising drug for LSCC therapy. GSK3ß might be a potential target to increase the anti-tumor effect of regorafenib in LSCC cells.

Evodiamine induces apoptosis and promotes hepatocellular carcinoma cell death induced by vorinostat via downregulating HIF-1α under hypoxia.

Hypoxia promotes HCC progression and therapy resistance, and there is no systemic treatment for HCC patients after sorafenib resistance. Thus, it is urgent to develop potential therapeutic regimens for HCC patients by targeting hypoxia signaling. In this study, we showed that evodiamine might be a potential therapeutic medicine for HCC by suppressing HIF-1α. In addition, evodiamine could sensitize the anti-HCC effect of vorinostat in HCC cells under hypoxia. Furthermore, evodiamine plus vorinostat accelerated the degradation of HIF-1α in HCC cells under hypoxia. In general, evodiamine might be a potential therapeutic candidate for HCC patients, and evodiamine combining with vorinostat might be an attractive chemotherapy strategy for HCC treatment.

Nedaplatin enhanced apoptotic effects of ABT-737 in human cancer cells via Mcl-1 inhibition.

Platinum compounds, such as cisplatin, carboplatin, oxaliplatin and nedaplatin, are widely used to treat a number of solid malignancies. Nedaplatin is a second-generation platinum complex, based on its pronounced anti-cancer activities against several solid tumors being equivalent to that of cisplatin, but with lower nephrotoxicity. In this context, the present study aimed to investigate the potential anti-cancer effect by combining nedaplatin with ABT-737. It was found that nedaplatin greatly increased ABT-737-mediated apoptosis in A549 and 95-D cells, accompanied by enhanced cleavage of poly(ADP-ribose) polymerase and caspase-3. In addition, this enhancement was also paralleled by cytochrome c release and dissipation of mitochondrial membrane potential. Additional mechanistic investigations revealed that nedaplatin plus ABT-737 exerted a synergistic effect on cancer cells through their ability to accelerate the degradation of Mcl-1. The present study has revealed nedaplatin as a pertinent sensitizer to ABT-737, which opens up new avenues for this promising BH3-mimetic molecule in the clinic.

Epothilone B induces apoptosis and enhances apoptotic effects of ABT-737 on human cancer cells via PI3K/AKT/mTOR pathway.

PURPOSE: Epothilone B and its derivatives are tested in multiple clinical trials. Epothilone B induces neurotoxic effect in clinical trials; however, low-dose epothilone B regimen can promote neuroprotection and neurogenesis. Thus, the study of new combination chemotherapy regimen incorporating low-dose epothilone B with other chemotherapeutic agents might help to develop epothilone B-based approaches to cancer treatment and avoid the neurotoxicity of epothilone B. METHODS: Cell proliferation was assessed by SRB cell viability assay. Apoptosis was analyzed by propidium iodide (PI) staining. Mitochondrial membrane depolarization was evaluated using JC-1 staining. The expression of proteins was detected by western blotting. RESULTS: In this study, we demonstrated that the combination of ABT-737 and low-dose epothilone B showed synergistic anti-proliferation effects on human cancer cells. In addition, epothilone B + ABT-737 synergy was through mitochondria-mediated apoptosis pathway. Furthermore, combination treatment markedly induced the activation of caspase-3 and the cleavage of PARP. The activation of PI3K/Akt/mTOR pathway is associated with resistance to epothilone B. Our data showed that epothilone B plus ABT-737 resulted in a blockade of the PI3K/AKT/mTOR signaling pathway. CONCLUSIONS: These data indicate that ABT-737 may be a pertinent sensitizer to epothilone B, and the strategy of combining epothilone B with ABT-737 appears to be an attractive option for overcoming the resistance and neurotoxicity of epothilone B.

Deacetylisovaltratum disrupts microtubule dynamics and causes G2/M-phase arrest in human gastric cancer cells in vitro.

AIM: Deacetylisovaltratum (DI) is isolated from the traditional Chinese herbal medicine Patrinia heterophylla Bunge, which exhibits anti-cancer activity. Here, we investigated the effects of DI on human gastric carcinoma cell lines in vitro and elucidated its anti-cancer mechanisms. METHODS: Human gastric carcinoma AGS and HGC-27 cell lines were treated with DI, and cell viability was detected with MTT assay. Cell cycle stages, apoptosis and mitochondrial membrane potential were measured using flow cytometry. Protein levels were analyzed by Western blotting. Tubulin polymerization assays and immunofluorescence were used to characterize the tubulin polymerization process. RESULTS: DI inhibited the cell viability of AGS and HGC-27 cells in a dose- and time-dependent manner with IC50 values of 12.0 and 28.8 µmol/L, respectively, at 24 h of treatment. Treatment with DI (10-100 µmol/L) dose-dependently promoted tubulin polymerization, and induced significant G2/M cell cycle arrest in AGS and HGC-27 cells. Moreover, DI treatment disrupted mitochondrial membrane potential and induced caspase-dependent apoptosis in AGS and HGC-27 cells. CONCLUSION: DI induces G2/M-phase arrest by disrupting tubulin polymerization in human gastric cancer cells, which highlights its potent anti-cancer activity and potential application in gastric cancer therapy.

Evodiamine induces apoptosis and enhances apoptotic effects of erlotinib in wild-type EGFR NSCLC cells via S6K1-mediated Mcl-1 inhibition.

Erlotinib is effective in NSCLC patients with known drug-sensitizing EGFR mutations, but its clinical efficacy in patients with wild-type EGFR or acquired resistance to erlotinib remains modest. Evodiamine is a chemical extracted from the Evodia rutaecarpa (Juss.) Benth, we showed that evodiamine could induce anti-proliferation and apoptosis in four wild-type EGFR NSCLC cell lines, and combining evodiamine with erlotinib might successfully inhibit cell proliferation and survival in wild-type EGFR NSCLC cells, characterized as erlotinib-resistant. In addition, evodiamine plus erlotinib significantly increased the apoptotic rate of NSCLC cells, as compared to single agent treatment alone. Further investigation of the mechanism underlying these effects revealed that evodiamine plus erlotinib might downregulate Mcl-1 expression through the mTOR/S6K1 control of its translation. Thus, our study has revealed evodiamine as a pertinent sensitizer to erlotinib and the strategy of combining erlotinib with evodiamine appears to be an attractive option for reversing resistance to erlotinib.